The present invention relates to a cathode ray tube such as a color television tube equipped with an antireflection film and a method of manufacturing a conductive antireflection film used in a cathode ray tube, etc.
In recent years, a serious problem is pointed out in a cathode ray tube such as a Brawn tube for a color television tube or a CRT for a computer. It is pointed out that an electromagnetic wave generated in the vicinity of the electron gun and deflection yoke within the cathode ray tube leaks to the outside so as to affect electronic equipment arranged around the cathode ray tube. In order to prevent the electromagnetic wave from leaking to the outside, a conductive antireflection film is formed on the surface of the face panel of the cathode ray tube.
Such a conductive antireflection film is disclosed in, for example, U.S. Pat. No. 4,785,217. Specifically, disclosed is a conductive antireflection layer consisting of an antireflection film containing particles of at least one of metals selected from the group consisting of Pd, Sn, Pt, Ag, and Au together with a metal oxide.
The conductive antireflection film is required to be capable of preventing the electromagnetic wave from leaking to the outside and, at the same time, to be capable of achieving a high contrast in order to enable the cathode ray tube to display a clear picture image.
The high contrast can be achieved by improving the light transmittance of the conductive antireflection film. However, if the conductive film is formed thin for improving the light transmittance in the conventional cathode ray tube, the density of the metal fine particles is lowered, resulting in failure to obtain a sufficient electrical conductivity. As a result, it is difficult to prevent the electromagnetic wave from leaking to the outside. On the other hand, if the thickness of the conductive film is increased in an attempt to improve the electrical conductivity, the density of the metal fine particles is increased, leading to a low light transmittance.
It should also be noted that, in the conventional conductive antireflection film, the fine particles of silver, silver-palladium alloy, etc. contained in the film causes the film to strongly absorb light having a wavelength of about 400 nm to 500 nm. It follows that the body color is rendered yellowish and poor in contrast, making it difficult to obtain a clear picture image.